Office chairs are known generally consisting of a support base provided with wheels or with a rotatable column of variable height, the upper end of which is inserted into a box support, the interior of which houses the adjustment mechanisms for the seating portion and back rest. The seating portion and back rest are generally securely coupled to their supports by suitable screws.
Solutions are currently sought for simplifying and accelerating the assembly of these components to enable self-assembly of the structure by the final user, by enabling the components (back rest, seating portion, support boxes, column and spokes) to be sent separately to achieve low-cost packaging and transport. Consequently the ability to reduce the size and weight of these components is of fundamental importance in achieving competitive products of quality.
In swivel chairs the back rest is hinged to a support box and supported in the movements which the user imposes on it by an elastic support element able to withstand the user's weight.